The present invention relates to key switches and relates more particularly to a mechanical key switch which is consisted of less number of parts, easy to assemble and inexpensive to manufacture.
FIG. 1 illustrates a mechanical key switch according to the prior art, which comprises a casing having a key cap for controlling a switching mechanism to operate. The switching mechanism is comprised of six parts, namely, a spring plate A, a plastic frame plate B, a first conducting plate C, a thin copper plate D, an insulator plate E, and a second conducting plate F. The plastic frame plate B has two opposite pins B3 disposed at a lower end for fastening the first conducting plate C, the thin copper plate D, the insulator plate E and the second conducting plate F together. Referring to FIG. 2, pressing down the key cap G causes the two spring arms Al of the spring plate A to carry a raised portion A 2 thereon to squeeze the trigger rod B2 in the center hole B1 of the plastic frame plate B to press on the thin copper plate D permitting the think copper plate D to project through the center hole E1 of the insulator plate E and then to firmly contact the second conducting plate F so as to form into a closed circuit. Because numerous parts are required to assemble into a key switch, assembly process is complicated, material as well as labor cost can not be reduced.